is a Polish professional football manager and former player. He was most recently in charge of Ekstraklasa club Jagiellonia Białystok.

Nowak played in Europe for Polish clubs such as Zawisza Bydgoszcz and Widzew Łódź, before going on to play in Turkey, Switzerland and Germany. He was voted one of the best players in the Bundesliga for the 1995–96 season while playing with 1860 Munich. He moved to the United States in 1998 and played four years with Chicago Fire. Nowak played for the Poland national football team throughout the 1990s, earning 24 caps, serving as national captain for several years, and being voted Polish Footballer of the Year in 1996.

As a coach, he is a former assistant coach of the United States men's national soccer team under Bob Bradley, former head coach of United States U-23 men's national soccer team, and former head coach of D.C. United and Philadelphia Union of MLS. However, his reputation in the USA took a big hit after he was accused of seriously mistreating and physically abusing players whilst being coach of the latter; an arbitration and a federal case that followed supported the charges in the accusations.

He had a brief stint whilst still a player in the United States as chairman of Górnik Konin, but was hugely unpopular and widely blamed for the club's demise. Over a decade later, he became technical and personal advisor to the president of Caribbean Football Union and technical director and head coach to the Antigua and Barbuda Football Association.